There’s good evidence that it helps reduce atherosclerosis, orhardening of the arteries. For people who have already had a heartattack, niacin seems to lower the risk of a second one. Inaddition, niacin is an FDA-approved treatment for pellagra, a rarecondition that develops from niacin deficiency.Niacin has also been studied as a treatment for many other healthproblems. There’s some evidence that it might help lower the riskof Alzheimer’s disease, cataracts, osteoarthritis, and type 1diabetes. However, more research needs to be done.